What planting zone is San Jose, CA?

San Jose is in USDA plant hardiness zone 9b (average annual extreme minimum temperature 25 to 30°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in San Jose?

In San Jose, CA the warmest month is August (avg high 82.7°F) and the coldest is December (avg low 42.8°F). It averages about 16.1″ of precipitation a year.

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San Jose, CA Planting Calendar & Frost Dates

USDA hardiness zone 9b · ZIP 95111 · elevation 20′ · NOAA & USDA data

San Jose sits in USDA zone 9b and is effectively frost-free — you can grow something outdoors year-round. The warmest month is August (avg high 82.7°F) and the coolest is December (avg low 42.8°F). Time plantings by the hot vs. cool season rather than by frost: grow heat-loving crops through the warm months and cool-season greens in the mild winter. The wettest month is February (3.2″).

Hardiness zone

min temp 25 to 30°F

Frost

Frost-free

grow year-round

Warmest month

August

avg high 82.7°F

Month-by-month typical weather in San Jose

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at San Jose, CA (6.2 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)
January	59	43.3	51.1	3
February	62.8	45.4	54.1	3.2
March	66.4	47.6	57	2.6
April	70	49.8	59.9	1.2
May	74.9	53.3	64.1	0.5
June	80.1	57	68.5	0.2
July	82.2	59.1	70.6	0
August	82.7	59.8	71.2	0
September	81.4	58.2	69.8	0.1
October	74.6	53.8	64.2	0.8
November	65	47.2	56.1	1.4
December	58.8	42.8	50.8	3.1

What to plant when in San Jose

San Jose is frost-free, so there's no last-frost date to time from. Grow cool-season crops (lettuce, peas, broccoli, carrots) in the cooler months and warm-season crops (tomatoes, peppers, beans, squash) through the warm season.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in California

Campbell, CA Santa Clara, CA Milpitas, CA Sunnyvale, CA Morgan Hill, CA Cupertino, CA Mountain View, CA Newark, CA

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — San Jose, CA, 6.2 mi (confidence: high). Monthly weather normals: San Jose, CA, 6.2 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.